John Libbey Eurotext

Environnement, Risques & Santé


Water from the Menoua watershed (Cameroon) and agricultural pollution: the chemical risks inherent in its consumption Volume 21, issue 2, March-April 2022


  • Figure 1
  • Figure 2
  • Figure 3
  • Figure 4
  • Figure 5
  • Figure 6
  • Figure 7


1 Département sciences alimentaires et nutrition
ENSAI, Université de Ngaoundéré
BP 455
2 Département chimie appliquée
Université de Ngaoundéré
BP 455
* Tirés à part

Water is a vital and invaluable natural wealth, with which Cameroon has the luck to be well-endowed in the case of Menoua. However, this abundance is not unlimited, and it is not a guarantee in itself that this resource will be available or accessible for human nutrition. Unfortunately, the populations of the Menoua watershed, like others in Cameroon, have long been unaware of these realities. Thus, the quality of this resource has deteriorated sharply since the country moved to second-generation agriculture, which involves the massive and uncontrolled use of fertilizers, and an apparently unlimited faith in them. To evaluate the impact of fertilizers used by farmers on the waters of Menoua and to estimate the level of health risk of the exposed populations, we analyzed the chemical parameters (nitrates, nitrites, ammonia, orthophosphates and sulfates) of 132 samples taken from 33 sites in two seasons: two in the dry seasons and two others in the rainy season. The results of these analyses revealed that the basin's waters are polluted by nitrogen and phosphates. This is confirmed by the high average concentrations, compared with the WHO standards, for nitrites (5.68 mg/L), ammonia (7.03 mg/L), and orthophosphates (1.49 mg/L). These values reflect the evidence of agricultural pollution. The hazard quotient or the estimated concentration of pollutants in water/drinking water quality standard ratio exceeds 1 for nitrites, ammonia, and orthophosphates. Populations drinking this water are therefore exposed to health risks. This is thus a public health problem, and it is time that the public authorities and society as a whole be made aware of it and take the necessary measures to protect this resource and the health of the population.